Following the Second World War, polymers, generally water soluble, were used to stabilize soils. Scientific literature, in the 50s, describes the use of different soil conditioning polymers as the Krilium® of the Monsato Chemical Company.
Several other polymers have been described afterwards to condition soils:                Synthetic polymers: for instance, homopolymers and copolymers of acrylamide, acrylic acid and its salts, methacrylic acid and its salts, acrylonitrile, vinylpyrolidone, vinylformamide, 2-acrylamido-2-methyl propane sulfonic acid and its salts, vinyl acetate, maleic acid or ethylene oxide and derivatives likes hydrolysed polyacrylonitrile, polyvinyl alcohol;        Natural polymers, natural gums, polysaccharides and their derivatives: galactomannan, guar gum, carob gum, xanthan gum, arabic gum, chitosan, carrageenan, pectins, starch, modified starches, alginates, celluloses, cellulose derivatives (cellulose ethers), agar-agar;        Grafted polymers: for instance, starch-acrylamide-acrylates, starch-acrylonitrile, chitosan-acrylic acid copolymers.        
Among all these polymers, polyacrylamides have been the focus of research and have been adopted for their efficiency in soil conditioning, reduction of soil erosion, increased water quality post irrigation and their low cost.
Polyacrylamide added to irrigation water has proven to decrease soil erosion drastically. Lentz and al. have applied polyacrylamide doses from 1 to 20 ppm in irrigation water (furrow irrigation) and have controlled erosion by 96% with the 10 ppm dose. Literature is abundant for this topic including the following article: “preventing irrigation furrow erosion with small application of polymers” published in the Soil Science Society of America Journal (1992, issue 56, pages 1926-1932).
The application of polyacrylamide (PAM), reduces the redistribution of fine soil particles in irrigation or rain water and prevents the formation of crust on the soil surface. Crust formation is caused by soil fines clogging the soil pores, leading to the formation of an impervious layer that restricts water and air movement into the soil profile. Seedlings have difficulty breaking through the crust, limiting the crops emergence. Seedling emergence can be improved by an application of polyacrylamide before the first rain event or prior to during the post-planting irrigation application.
The ability of polyacrylamide to flocculate the solids out of the irrigation and runoff water also prevents the discharge of nutrients and pesticides which have attached to the soil particles. By limiting the amount of soil, nutrient, and pesticide runoff, polyacrylamide helps improve the water quality post-irrigation, reduces the turbidly of the tail water, and helps improve the “health” of the drainage ecosystem. For these reasons polyacrylamide is a valuable conservation tool used to address the water quality in production agriculture.
By binding smaller particles together, polyacrylamide helps increase the particle size. The larger particle size decreases pore clogging, increases soil uniformity, and increases infiltration rates. All of these factors allow for better wetting of the soil profile and more efficient use of water, which can lead to yield increases and a decrease in irrigation cost.
Water soluble polymers have several benefits as described above. However, their application on the soil is limited to irrigation periods and it is often limited by the number of irrigation cycles during the growing season. Currently irrigation water is the primary method of application of these products.
If the irrigation water source is a canal water, typically the water is treated in the canal using the dry form of polyacrylamide and is applied using a granular applicator. The polymer is dosed into the water and the water is pulled out the canal.
If the irrigation water is a well, polyacrylamide, in emulsion form is injected either at the well head or in-field riser. The riser being the point in the field where the water is delivered. In most cases, a well supplies multiple risers for a total of 140 to −200 acres on average.
The delivery of the water from the canals and wells differs in application. Most canal irrigated scenarios use a form of suction tube to pull water out of the canal. Each tube is placed in either every row or every other raw. In a well scenario the water is pumped out of the riser in a “Poly pipe”. Poly Pipe is a large inflatable roll of plastic pipe than runs along the high side of a field. The irrigator then pokes holes in the pipe to release the water. The number of holes and spacing of holes are determined by the target volume raw spacing. A computer program is typically used to determine the size and number of holes in a run of Poly pipe.
Patent application PCT/FR2014/051863 describes a soil conditioning process to apply a water or swellable polymer to the soil consisting in preparing polymer in a concentrated liquid form and in applying this preparation on the surface of a support in rotation around its axis of revolution in order to create droplets which are spreaded to the soil. This process allows to apply soil conditioning polymer without irrigation system but the concerned support in rotation is fixed for instance on a tractor and so application is time consuming if large surfaces have to be treated.